An international team of scientists believes they have finally found the elusive answer to the question of why moths are attracted to light. Artificial light appears to trap moths and other flying insects in erratic flight patterns. They are used to following lights in the night sky rather than on the ground, so light robs them of their sense of up and down. Moths are not necessarily attracted to light, but they are more likely to become trapped within it. Here are the findings: The study was published in the journal Jan. 30 connection with nature.
[Related: Light pollution is messing with coral reproduction.]
millions of years of evolution
Moths and butterflies call Earth home at least 200 million years. meanwhile,
Moths and other insects that fly at night may have evolved to tilt their heads back toward the brightest direction. Originally, this light source was not from the ground, but from the stars and moon in the sky. This allowed the insect to know which way was pointing up and maintain level flight.
When artificial light sources began filling the Earth, moths turned away from street lights and fire. So the instincts they learned through millions of years of evolution led them to fly around streetlights in endless loops.
“This is a question from prehistoric times. In early writings, people were aware of this around fires,” says study co-author Jamie Theobald, a biologist at Florida International University. stated in a statement. “All of our speculations about why that happens turned out to be wrong. So this is definitely the coolest project I’ve been a part of.”
Flight path monitoring
inside studyAn international team of researchers in the Costa Rican cloud forest used high-resolution, high-speed infrared video recording to capture the flight paths of insects around artificial light. They collected more than 477 videos spanning more than 11 insect orders. This technique was able to capture the insect’s fast and crazy trajectory through light and was used to reconstruct the points of the insect’s flight path in his three dimensions. The researchers noticed that moths and dragonflies appeared to turn away from the artificial light and drastically change their flight paths. The insects may have thought that the light came from a light source in the sky rather than on the ground.
“If the light is above them, they may start circling around the light, but if the light is behind them, they may start to lean back and rise until it stalls,” the study says. says Sam Fabian, co-author and entomologist at Imperial College London. Said guardian. “More dramatic is when they fly directly over the lights, which can tip over and lead to accidents. That just suggests that the moth is confused about which one is on top.”
There are several things in research Entomologists are buzzingBecause it provides potential answers to natural phenomena that are millions of years old.
conservation concerns
This study is the first known record of this behavior in a nocturnal insect and provides a new explanation for why light seems to attract moths. While this appears to confirm that light is destructive, it also provides new insights into conservation concerns. The main cause of recent insect population declines is light pollution. Moths and other insects can become trapped within the lights and become easy prey for bats. False light tricks moths into believing it’s daytime, A signal that it’s time to sleep without eating.
[Related: City lights could trigger a baby boom for some moths and butterflies.]
This study also suggests that light direction is important when designing and installing outdoor lighting. The worst direction, the researchers say, is upwards or a bare bulb. Covering or shielding the bulb may offset the negative effects.
Scientists are also starting to think about how the color of light affects flying nocturnal insects. How these insects are attracted to distant lights in the first place also remains an unexplained mystery.
“Before, we were told, why shouldn’t you ask these questions? There’s no point,” said Yash Sondhi, a postdoctoral fellow at the Florida Museum of Natural History and co-author of the study. stated in a statement. “But by persevering and finding the right people, we came up with an answer that no one else had thought of. But it also helped raise awareness of how light affects insect populations. , which is very important to signal changes that can help insects.”